Fluidic adjustable choke

ABSTRACT

A surface well choke system has a flow chamber and a fluid switch. The flow chamber has a first flow chamber inlet with more resistance to flow to an outlet than a second flow chamber inlet has to flow to the outlet. The fluid switch has a first flow path from a fluid switch inlet to the first flow chamber inlet, a second flow path from the fluid switch inlet to the second flow chamber inlet, and a movable flow deflector upstream of the first and second flow paths. The movable flow deflector is actuable to deflect flow from the fluid switch inlet to the first flow path or the second flow path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C.§371 and claims the benefit of priority to International ApplicationSerial No. PCT/US2013/078288, filed on Dec. 30, 2013, the contents ofwhich are hereby incorporated by reference.

BACKGROUND

The present disclosure relates to surface well choke systems and methodsfor controlling the flow of fluid to and from a well.

Surface well choke systems used on production wells typically restrictfluid flow from an inlet to an outlet by a manually adjustable handwheel or power actuator that moves a tapered stem into and out of achoke seat. These types of choke mechanisms are imprecise and slow torespond to change the fluid restriction. Additionally, the interfacebetween the tapered stem and seat is subject to debris contamination anderosion over time.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic partial cross-sectional view of an example wellsystem with a surface well choke system.

FIGS. 2A and 2B are a schematic cross-sectional front view (FIG. 2A) anda side view (FIG. 2B) of an example well choke that can be used in thesurface well choke system of FIG. 1.

FIG. 3 is a schematic cross-sectional view of an example well chokesystem incorporating an example bypass.

FIG. 4 is a schematic cross-sectional view of an example well chokesystem incorporating parallel well chokes.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Referring first to FIG. 1, an example well system 10 includes asubstantially cylindrical wellbore 12 that extends from a wellhead 14 atthe surface 16 downward into the Earth into one or more subterraneanzones of interest 18 (one shown). In certain instances, the formationsof the subterranean zone are hydrocarbon bearing, such as oil and/or gasdeposits, and the well system 10 will be used in producing thehydrocarbons and/or used in aiding production of the hydrocarbons fromanother well (e.g., as an injection or observation well). Notably, theexample well system 10 is described herein for convenience of referenceonly, and the concepts herein are applicable to virtually any type ofwell. The wellhead 14 has a flange 22 for attaching equipment to thewellhead 14. A well choke system 24 is shown attached to the wellhead14, for example, by a corresponding wellhead attachment flange 23 of thechoke system 24 being bolted and/or otherwise affixed to the flange 22.The well choke system 24 is further shown coupled to pipeline 26, forexample, a production or injection pipe. Fluids travel between thewellbore 12 and the pipeline, through the wellhead 14 and well chokesystem 24.

Referring to FIGS. 2A and 2B, an example well choke 100 that can be usedin a well choke system 24 is shown in a detail cross-sectional frontview and a side view, respectively, to show the working aspects of thechoke. The well choke 100 controls the flow of fluid from its inlet toits outlet, or in the context of the well system 10 of FIG. 1, the flowbetween the wellhead 14 and pipeline 26. In certain instances, the wellchoke 100 is full bore, where the smallest flow area through the choke100, including an inlet and outlet of the choke 100, is the same(precisely or substantially) or larger than the flow area through thewellhead 14. In certain instances, the smallest diameters through theinlet and the outlet of the choke 100 are the same as or larger than thebore diameter of the wellhead 14. In other instances, the well choke 100can have other, different flow areas or inner diameters.

The well choke 100 has a main body 101 that internally defines a fluidswitch 102 and a variable flow resistance flow chamber 104. The inlet tothe fluid switch 102 functions as an inlet of the well choke 100. Thefluid switch 102, as discussed in more detail below, determines the pathof the fluid flow through the well choke 100. The outlet from flowchamber 104 functions as an outlet of the well choke 100 and housespathways of high and low flow rate reduction.

The flow chamber 104 has an indirect flow chamber inlet 106 and a directflow chamber inlet 108, where the indirect flow chamber inlet 106presents a flow path with more resistance to flow to an exit outlet 110than the direct flow chamber inlet 108. The exit outlet 110 suppliesfluid to the outlet of the well choke 100. The flow chamber 104 has asidewall 105 apart from the exit outlet 110 and that defines the flowchamber inlets 106 and 108. FIGS. 2A and 2B show a generally disk shapedchamber, where the sidewall 105 is curved to form a circular shape andthe chamber has a low height to diameter aspect ratio. The exit outlet110 is shown as circular opening in an end wall, near the center of theflow chamber 104, and in certain instances, with a center on the centeraxis of the flow chamber 104. In other instances, the shape of thechamber, shape of the sidewalls, exit location, exit orientation and/orexit shape could be different. For example, the chamber need not be diskshaped, but rather could be rectangular, spherical, and/or other shape.

The indirect flow chamber inlet 106 opens an indirect flow path 114 tothe flow chamber 104 and directs incoming flow in a trajectory that isnot directly toward the exit outlet 110. This indirect trajectoryprovides a higher reduction in flow rate towards the exit outlet 110than a more direct trajectory would, because instead of flowing directlytoward the outlet 110, the flow tends to circle the outlet 110 insequentially smaller circles until it reaches the outlet 110. Ininstances having a curved sidewall 105, the curvature of the sidewall105 facilitates this circling by redirecting impinging and nearby flowto circle around the outlet 110. In certain instances, the inlet 106directs flow in a trajectory parallel to the tangent of the curvedsidewall 105. The indirect flow chamber inlet 106 results in restrictionin net fluid flow rate while substantially maintaining flow velocityfrom the indirect flow chamber inlet 106 to the exit outlet 110, becausethe restriction is produced by the longer flow path and not a reductionin flow area. This rapidly reduces fluid flow rate while maintaining alarge pressure drop.

The direct flow chamber inlet 108 opens a direct flow path 116 to theflow chamber 104 and directs incoming flow more directly to the exitoutlet 110 than the indirect flow inlet 106. In certain instances, thedirect flow chamber inlet directs incoming flow directly to the outlet110, for example, radially in an embodiment having a circular exitoutlet 110. This more direct flow provides lower reduction in fluid flowrate towards the exit outlet 110 than the fluid flow from the indirectinlet 106, because the flow tends to flow in a substantially straightand direct path from the direct flow chamber inlet 108 to the exitoutlet 110. In certain instances, the direct flow chamber inlet 108additionally has an island along the centerline of the direct flowchamber inlet 108 that straightens fluid flow as it passes through thedirect flow chamber inlet 108 toward the exit outlet 110.

The fluid switch 102 controls the path, and thus the resistance to flowrate, of the fluid flow through the well choke 100. The fluid switch 102has a fluid switch inlet 112, the indirect flow path 114 directedtowards the indirect flow chamber inlet 106, the direct flow path 116directed towards the direct flow chamber inlet 108, and a movable flowdeflector 118.

The fluid switch 102 is upstream relative to the flow chamber 104. Thefluid switch inlet 112 receives flow from the inlet to the choke 100. Incertain instances, the fluid switch inlet 112 has the same flow area(e.g., same diameter) as the exit outlet 110 of the flow chamber 104. Inother instances, the flow area of the exit outlet 110 and fluid switchinlet 112 can be different. In certain instances, the direct flow path116 is linear (substantially or precisely) from the fluid switch inlet112 to the direct flow chamber inlet 108, tracking along a sidewall ofthe fluid switch 102. The fluid switch 102 also has an angled offsetpathway that defines the indirect flow path 114. As shown, the indirectflow path 114 tracks a curved sidewall leading to the indirect flowchamber inlet 106, but could be shaped differently.

The movable flow deflector 118 is located upstream of the indirect flowpath 114 and direct flow path 116. The deflector 118 is moved in theflow by an actuator 119. The flow deflector 118 is shown residingopposite the indirect flow path 114. Thus, movement of the flowdeflector 118 into the flow, toward the indirect flow path 114 deflectsthe fluid flow down the indirect flow path 114, or movement of thedeflector 118 out of the flow, away from the indirect flow path 114,allows the fluid to flow down the direct flow path 116. The fluiddeflector 118 need not fully close off the direct flow path 116 todirect flow down the indirect flow path 114, but rather creates aperturbation to the flow that tends to deflect the flow to the indirectflow path 114. Displacing the deflector 118 from flush with the wall ofthe inlet 112 to 20%-30% of the transverse dimension of the flow area(e.g., diameter) is enough to deflect the fluid flow to flow(substantially or wholly) along the indirect flow path 114. In otherapplications, depending on flow rate and shape of the deflection,displacing the deflection 118 from flush with the wall of the inlet to10% of the transverse dimension of the flow area is enough to deflectthe flow while in other applications, displacements in excess of 50% areneeded. No displacement of the movable flow deflector 118 into the inletflow path of the fluid switch 102 allows the fluid to flow along thedirect flow path 116. Notably, the moveable flow deflector 118 need notbe moved to its full extent into the flow. For example, the flowdeflector 118 can be continuously adjustable between a retractedposition (e.g., flush with the wall of the inlet 112 or other) and itsfull extent. Each intermediate position provides a different degree ofperturbation to the flow, and thus, deflects different amounts of flowalong the direct flow path 116 and the indirect flow path 114. Also,although only one flow deflector 118 is shown in FIGS. 2A and 2B, inother instances, more than one could be provided. In certain instances,multiple flow deflectors 118 are provided on the same side of the flow,on opposite sides of the flow or otherwise arranged.

The actuator 119 of the movable flow deflector 118 can take many forms.In certain instances, the actuator 119 is a solenoid, locking solenoid,piezoceramic, voice coil, motor, magnetostrictor, ferroelectric, relaxorferroelectric, pump, bellow, blower, a combination thereof, and/orothers.

Referring to FIG. 3, another configuration of well choke 100′ that canbe used in a well choke system 24 is shown in front cross-sectionalview. The well choke 100′ is like the choke 100 of FIGS. 2A and 2B,including a fluid switch 102, moveable flow deflector 118, indirect flowpath 114, direct flow path 116, variable flow resistance flow chamber104, and exit outlet 110. The well choke 100′ additionally has aparallel bypass flow path 200 that allows a portion of the flow throughthe choke 100′ to bypass (and thus not flow through) the fluid switch102 and flow chamber 104. The bypass 200 lessens the effect of the flowchamber 104 in changing the total flow through the choke 100′.

Referring to FIG. 4, another configuration of well choke 100″ that canbe used in a well choke system 24 is shown in front cross-sectionalview. The well choke 100″ has two parallel paths, each with its ownfluid switch 102, moveable flow deflector 118, indirect flow path 114,direct flow path 116, variable flow resistance flow chamber 104, andexit outlet 110. In other instances, additional parallel paths, with orwithout a switch, deflector and chamber, can be provided. The moveableflow deflectors 118 can be actuated independently, allowing none, one orboth of the flow chambers 104 to provide resistance at a given time.Therefore, instead of providing binary changes in flow resistance, thetwo parallel paths can provide at least three different degrees of flowresistance. Additional parallel paths can enable providing additionaldegrees of flow resistance. Arrangements like FIG. 4 can also include abypass path, like bypass path 200.

Referring back to FIG. 1, in certain instances, the well choke system 24has a controller 120 communicably coupled to the actuator or actuators(e.g., actuator 119) of the choke (e.g., choke 100, 100′ or 100″) tocontrol flow through the choke. The controller 120 can respond to a userinput and/or an input from another controller, computer or other. Thecontroller 120 can operate the actuator to a steady state positionand/or operate the actuator at a specified duty cycle. Because the flowdeflector need not move across the entire flow area and need not beconfigured to seal the entire flow area, it can be lightweight and movedquickly. In certain instances, the flow deflector can be moved at a dutycycle of between 0.001 Hertz and 1 Hertz, and in certain instances, upto 100 Hertz or higher. The controller 120 and the actuator of the flowdeflector can be coupled by wire (electrical, optical and/or other) orwireless connection.

In certain instances, the well choke system 24 includes or accesses oneor more sensors 122 to sense a characteristic of fluid that flowsthrough the well choke and/or other characteristics apart from the fluidthat flows through the well choke. The one or more sensors 122 measurepressure, velocity, mass flow rate, volumetric flow rate, viscosity,and/or other characteristics. For example, in certain instances, asensor 122 is in the flow path upstream or downstream of the flowdeflector, in the choke, in the wellbore (as shown) or elsewhere. Theone or more sensors 122 are communicably coupled to the controller 120,allowing the controller 120 to operate the choke based on the output ofthe one or more sensors 122. The sensor 122 and the controller 120 canbe coupled by wire or wireless connection. In certain instances, thecontroller 120 can operate in a closed loop feedback loop based on theoutput of the one or more sensors 122.

Certain aspects encompass, a surface well choke system includes a flowchamber and a fluid switch. The flow chamber includes a first flowchamber inlet that has more resistance to flow to an outlet than asecond flow chamber inlet has to flow to the outlet. The fluid switchincludes a first flow path from a fluid switch inlet to the first flowchamber inlet, a second flow path from the fluid switch inlet to thesecond flow chamber inlet, and a movable flow deflector upstream of thefirst and second flow paths that is actuable to deflect flow from thefluid switch inlet to the first flow path or the second flow path.

Certain aspects encompass, a fluid flow is directed from a wellheadthrough a first flow path of a surface well choke to an outlet of thesurface well choke with a first flow resistance. A fluid deflector movesinto the fluid flow and directs the fluid flow through a second,different flow path of the surface well choke to the outlet with asecond, different flow resistance.

Certain aspects encompass, a surface well choke system includes a flowchamber and a fluid switch. The flow chamber includes a first flowchamber inlet that has more resistance to flow to an outlet than asecond flow chamber inlet has to flow to the outlet. The fluid switchincludes a first flow path from a fluid switch inlet to the first flowchamber inlet, a second flow path from the fluid switch inlet to thesecond flow chamber inlet, and a movable flow deflector upstream of thefirst and second flow paths that is actuable to deflect flow from thefluid switch inlet to the first flow path or the second flow path. Acontroller communicably coupled to an actuator of the movable flowdeflector operates the actuator upon user input.

Implementations can include some, none, or all of the followingfeatures. The surface well choke system includes a controllercommunicably coupled to an actuator of the moveable flow deflector. Thecontroller operates the actuator in encoding information as pressurepulses into fluid flowing through the surface well choke system. Thecontroller operates the actuator at a specified duty cycle. The dutycycle includes rates of 0.001 to 1 Hertz. The movable flow deflectorresides in an inlet flow path of the fluid switch, and the actuatorstroke is 30% or less of the diameter of the inlet flow path. Thesurface well choke system includes a sensor to sense a characteristic offluid that flows through the surface well choke system. The fluid switchincludes a wellhead attachment flange. The first flow chamber inlet isan indirect flow inlet and the second flow chamber inlet is a directflow inlet that is oriented to direct incoming flow more directly to theoutlet than the indirect flow inlet. The flow chamber includes a curvedsidewall apart from the outlet, where the indirect flow inlet isoriented to direct incoming flow substantially parallel to a tangent ofthe curved sidewall and the direct inlet is oriented to direct incomingflow at the outlet. The surface well choke system includes a bypass flowpath to bypass flow around the flow chamber and the fluid switch,including an inlet about the inlet to the fluid switch and an outletabout the outlet of the flow chamber. The surface well choke systemincludes a second flow chamber and a second fluid switch in fluidicparallel to the first mentioned flow chamber and first mentioned fluidswitch. Directing a fluid flow includes moving the fluid deflector inthe fluid flow to an initial position and directing the fluid flowthrough the first flow path. The fluid deflector is cycled between aninitial position and another position at a rate of 0.001 to 1 Hertz.Directing the fluid flow through the second flow path includes directingthe fluid flow through an indirect path to the outlet and directing thefluid flow through the first flow path includes directing the fluid flowthrough a more direct path to the outlet. A portion of the fluid flow isdirected through a bypass while another portion of the fluid flow isconcurrently directed through the first flow path or the second flowpath. The surface well choke system includes at least one sensorcommunicably coupled to the controller to sense a characteristic offluid that flows through the well choke system. The surface well chokesystem includes a first sensor upstream of the flow chamber to sense afirst characteristic of fluid, and a second sensor downstream of theflow chamber to sense a second characteristic of fluid.

A number of embodiments have been described. Nevertheless, it will beunderstood that various modifications may be. Accordingly, otherembodiments are within the scope of the following claims.

What is claimed is:
 1. A surface well choke system, comprising: a flowchamber comprising a first flow chamber inlet that has more resistanceto flow to an outlet than a second flow chamber inlet has to flow to theoutlet; and a fluid switch comprising: a first flow path from a fluidswitch inlet to the first flow chamber inlet; and a second flow pathfrom the fluid switch inlet to the second flow chamber inlet; a movableflow deflector actuable to deflect flow from the fluid switch inlet tothe first flow path or the second flow path.
 2. The surface well chokesystem of claim 1, where the movable flow deflector is between aretracted position and an extended position and continuously adjustabletherebetween.
 3. The surface well choke system of claim 1, comprising acontroller communicably coupled to an actuator of the movable flowdeflector, the controller to operate the actuator at a specified dutycycle.
 4. The surface well choke system of claim 3, where the controlleris to operate the actuator at a specified duty cycle of 0.001 to 1Hertz.
 5. The surface well choke system of claim 3, where the movableflow deflector resides in an inlet flow path of the fluid switch, andthe actuator stroke is 30% or less of the diameter of the inlet flowpath.
 6. The surface well choke system of claim 1, comprising: a sensorto sense a characteristic of fluid that flows through the surface wellchoke system; and a controller communicably coupled to an actuator ofthe moveable flow deflector, the controller to operate the actuator. 7.The surface well choke system of claim 1, where the fluid switchcomprises a wellhead attachment flange.
 8. The surface well choke systemof claim 1, where the first inlet comprises an indirect flow inlet andthe second inlet comprises a direct flow inlet that is oriented todirect incoming flow more directly to the outlet than the indirect flowinlet.
 9. The surface well choke system of claim 8, where the flowchamber comprises a curved sidewall apart from the outlet; and where theindirect inlet is oriented to direct incoming flow substantiallyparallel to a tangent of the curved sidewall and the direct inlet isoriented to direct incoming flow at the outlet.
 10. The surface wellchoke system of claim 1, comprising a bypass flow path to bypass flowaround the flow chamber and the fluid switch, comprising an inlet aboutthe inlet to the fluid switch and an outlet about the outlet of the flowchamber.
 11. The surface well choke system of claim 1, comprising asecond flow chamber and a second fluid switch in fluidic parallel to thefirst mentioned flow chamber and first mentioned fluid switch.
 12. Amethod, comprising: directing a fluid flow from a wellhead through afirst flow path of a surface well choke to an outlet of the surface wellchoke with a first flow resistance; moving a fluid deflector in thefluid flow; and directing the fluid flow, with the fluid deflector,through a second, different flow path of the surface well choke to theoutlet with a second, different flow resistance.
 13. The method of claim12, comprising moving the fluid deflector in the fluid flow to aninitial position and directing the fluid flow through the first flowpath.
 14. The method of claim 13, comprising cycling the fluid deflectorbetween the initial position and another position at a rate of 0.001 to1 Hertz.
 15. The method of claim 12, where directing the fluid flowthrough the second flow path comprises directing the fluid flow throughan indirect path to the outlet and directing the fluid flow through thefirst flow path comprises directing the fluid flow through a more directpath to the outlet.
 16. The method of claim 12, comprising directing aportion of the fluid flow through a bypass concurrently while directinganother portion of the fluid flow through the first flow path and thesecond flow path.
 17. A surface well choke system, comprising: a flowchamber comprising a first flow chamber inlet that has more resistanceto flow to an outlet than a second flow chamber inlet has to flow to theoutlet; a fluid switch comprising: a first flow path from a fluid switchinlet to the first flow chamber inlet; a second flow path from the fluidswitch inlet to the second flow chamber inlet; and a movable flowdeflector actuable to deflect flow from the fluid switch inlet to thefirst flow path or the second flow path; and a controller communicablycoupled to an actuator of the movable flow deflector, the controller tooperate the actuator upon user input.
 18. The surface well choke systemof claim 17, comprising at least one sensor communicably coupled to thecontroller to sense a characteristic of fluid that flows through thewell choke system.
 19. The surface well choke system of claim 18,comprising: a first sensor upstream of the flow chamber to sense a firstcharacteristic of fluid; and a second sensor downstream of the flowchamber to sense a second characteristic of fluid.